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The broad term fire culture covers a wide spectrum of practices that use fire in agrarian contexts. Gösta Berg distinguishes between svedjning and svedjebruk. The general term svedjning includes clearing woodland and bushes, for example. Svedjebruk – or swidden cultivation – is defined as “burning woodland in order to grow cereals for a short period”. The technique is also called rågsvedja (from råg, the Swedish for “rye”). Swidden cultivation distinguishes between large-scale gransvedja (also called huuhtasvedja) and small-scale kaskisvedja. (Gransvedja derives from gran, the Swedish for “spruce”; kaskisvedja comes from kaske, an old Finnish word for “birch”.) The huuhta technique, associated with swidden cultivation in Savolax and Karelia, was introduced by 16th- and 17th-century Finnish settlers in Swedish counties including Värmland, Hälsingland, Medelpad and Ångermanland. In parallel with this, and much earlier too, small-scale swiddening was practised across much of the Svealand and Götaland regions.The prevalence of swidden cultivation in Southern Sweden has probably been underestimated, both in terms of its scale and effects on woodland and other vegetation. Regional legislation and early survey maps show that swidden was carried out across Southern and Central Sweden from the Middle Ages onwards. A swidden was temporary; vegetation regenerated within a couple of years, and new plots were continually exploited. Twenty or thirty years later would see a return to the initial plot, which would be cleared and burned once more. The practice entailed a systematic, recurrent burning of outfields. In the past, one consequence of this repeated swiddening of village outfields would have been a dearth of contiguous ancient woodland in Southern and Central Sweden.A swidden yielded roughly three times that of a permanent field. Cereals from wooded and semi-wooded areas would have been produced mostly by swidden cultivation, and the technique was probably vital for agricu

The broad term fire culture covers a wide spectrum of practices that use fire in agrarian contexts. Gösta Berg distinguishes between svedjning and svedjebruk. The general term svedjning includes clearing woodland and bushes, for example. Svedjebruk – or swidden cultivation – is defined as “burning woodland in order to grow cereals for a short period”. The technique is also called rågsvedja (from råg, the Swedish for “rye”). Swidden cultivation distinguishes between large-scale gransvedja (also called huuhtasvedja) and small-scale kaskisvedja. (Gransvedja derives from gran, the Swedish for “spruce”; kaskisvedja comes from kaske, an old Finnish word for “birch”.) The huuhta technique, associated with swidden cultivation in Savolax and Karelia, was introduced by 16th- and 17th-century Finnish settlers in Swedish counties including Värmland, Hälsingland, Medelpad and Ångermanland. In parallel with this, and much earlier too, small-scale swiddening was practised across much of the Svealand and Götaland regions.The prevalence of swidden cultivation in Southern Sweden has probably been underestimated, both in terms of its scale and effects on woodland and other vegetation. Regional legislation and early survey maps show that swidden was carried out across Southern and Central Sweden from the Middle Ages onwards. A swidden was temporary; vegetation regenerated within a couple of years, and new plots were continually exploited. Twenty or thirty years later would see a return to the initial plot, which would be cleared and burned once more. The practice entailed a systematic, recurrent burning of outfields. In the past, one consequence of this repeated swiddening of village outfields would have been a dearth of contiguous ancient woodland in Southern and Central Sweden.A swidden yielded roughly three times that of a permanent field. Cereals from wooded and semi-wooded areas would have been produced mostly by swidden cultivation, and the technique was probably vital for agricu

The broad term fire culture covers a wide spectrum of practices that use fire in agrarian contexts. Gösta Berg distinguishes between svedjning and svedjebruk. The general term svedjning includes clearing woodland and bushes, for example. Svedjebruk – or swidden cultivation – is defined as “burning woodland in order to grow cereals for a short period”. The technique is also called rågsvedja (from råg, the Swedish for “rye”). Swidden cultivation distinguishes between large-scale gransvedja (also called huuhtasvedja) and small-scale kaskisvedja. (Gransvedja derives from gran, the Swedish for “spruce”; kaskisvedja comes from kaske, an old Finnish word for “birch”.) The huuhta technique, associated with swidden cultivation in Savolax and Karelia, was introduced by 16th- and 17th-century Finnish settlers in Swedish counties including Värmland, Hälsingland, Medelpad and Ångermanland. In parallel with this, and much earlier too, small-scale swiddening was practised across much of the Svealand and Götaland regions.The prevalence of swidden cultivation in Southern Sweden has probably been underestimated, both in terms of its scale and effects on woodland and other vegetation. Regional legislation and early survey maps show that swidden was carried out across Southern and Central Sweden from the Middle Ages onwards. A swidden was temporary; vegetation regenerated within a couple of years, and new plots were continually exploited. Twenty or thirty years later would see a return to the initial plot, which would be cleared and burned once more. The practice entailed a systematic, recurrent burning of outfields. In the past, one consequence of this repeated swiddening of village outfields would have been a dearth of contiguous ancient woodland in Southern and Central Sweden.A swidden yielded roughly three times that of a permanent field. Cereals from wooded and semi-wooded areas would have been produced mostly by swidden cultivation, and the technique was probably vital for agricu

The broad term fire culture covers a wide spectrum of practices that use fire in agrarian contexts. Gösta Berg distinguishes between svedjning and svedjebruk. The general term svedjning includes clearing woodland and bushes, for example. Svedjebruk – or swidden cultivation – is defined as “burning woodland in order to grow cereals for a short period”. The technique is also called rågsvedja (from råg, the Swedish for “rye”). Swidden cultivation distinguishes between large-scale gransvedja (also called huuhtasvedja) and small-scale kaskisvedja. (Gransvedja derives from gran, the Swedish for “spruce”; kaskisvedja comes from kaske, an old Finnish word for “birch”.) The huuhta technique, associated with swidden cultivation in Savolax and Karelia, was introduced by 16th- and 17th-century Finnish settlers in Swedish counties including Värmland, Hälsingland, Medelpad and Ångermanland. In parallel with this, and much earlier too, small-scale swiddening was practised across much of the Svealand and Götaland regions.The prevalence of swidden cultivation in Southern Sweden has probably been underestimated, both in terms of its scale and effects on woodland and other vegetation. Regional legislation and early survey maps show that swidden was carried out across Southern and Central Sweden from the Middle Ages onwards. A swidden was temporary; vegetation regenerated within a couple of years, and new plots were continually exploited. Twenty or thirty years later would see a return to the initial plot, which would be cleared and burned once more. The practice entailed a systematic, recurrent burning of outfields. In the past, one consequence of this repeated swiddening of village outfields would have been a dearth of contiguous ancient woodland in Southern and Central Sweden.A swidden yielded roughly three times that of a permanent field. Cereals from wooded and semi-wooded areas would have been produced mostly by swidden cultivation, and the technique was probably vital for agricu

The broad term fire culture covers a wide spectrum of practices that use fire in agrarian contexts. Gösta Berg distinguishes between svedjning and svedjebruk. The general term svedjning includes clearing woodland and bushes, for example. Svedjebruk – or swidden cultivation – is defined as “burning woodland in order to grow cereals for a short period”. The technique is also called rågsvedja (from råg, the Swedish for “rye”). Swidden cultivation distinguishes between large-scale gransvedja (also called huuhtasvedja) and small-scale kaskisvedja. (Gransvedja derives from gran, the Swedish for “spruce”; kaskisvedja comes from kaske, an old Finnish word for “birch”.) The huuhta technique, associated with swidden cultivation in Savolax and Karelia, was introduced by 16th- and 17th-century Finnish settlers in Swedish counties including Värmland, Hälsingland, Medelpad and Ångermanland. In parallel with this, and much earlier too, small-scale swiddening was practised across much of the Svealand and Götaland regions.The prevalence of swidden cultivation in Southern Sweden has probably been underestimated, both in terms of its scale and effects on woodland and other vegetation. Regional legislation and early survey maps show that swidden was carried out across Southern and Central Sweden from the Middle Ages onwards. A swidden was temporary; vegetation regenerated within a couple of years, and new plots were continually exploited. Twenty or thirty years later would see a return to the initial plot, which would be cleared and burned once more. The practice entailed a systematic, recurrent burning of outfields. In the past, one consequence of this repeated swiddening of village outfields would have been a dearth of contiguous ancient woodland in Southern and Central Sweden.A swidden yielded roughly three times that of a permanent field. Cereals from wooded and semi-wooded areas would have been produced mostly by swidden cultivation, and the technique was probably vital for agricu

Traditional tropical agriculture often entails a form of slash-and-burn land management that may adversely affect ecosystem services such as pollination, which are required for successful crop yields. The Yucatán Peninsula of Mexico has a >4000 year history of traditional slash-and-burn agriculture, termed ‘milpa’. Hot ‘Habanero’ chilli is a major pollinator-dependent crop that nowadays is often grown in monoculture within the milpa system.We studied 37 local farmers’ chilli fields (sites) to evaluate the effects of landscape composition on bee communities. At 11 of these sites, we undertook experimental pollination treatments to quantify the pollination of chilli. We further explored the relationships between landscape composition, bee communities and pollination service provision to chilli.Bee species richness, particularly species of the family Apidae, was positively related to the amount of forest cover. Species diversity decreased with increasing proportion of crop land surrounding each sampling site. Sweat bees of the genus Lasioglossum were the most abundant bee taxon in chilli fields and, in contrast to other bee species, increased in abundance with the proportion of fallow land, gardens and pastures which are an integral part of the milpa system.There was an average pollination shortfall of 21% for chilli across all sites; yet the shortfall was unrelated to the proportion of land covered by crops. Rather, chilli pollination was positively related to the abundance of Lasioglossum bees, probably an important pollinator of chilli, as well indirectly to the proportion of fallow land, gardens and pastures that promote Lasioglossum abundance.Synthesis and applications. Current, low-intensity traditional slash-and-burn (milpa) agriculture provides Lasioglossum spp. pollinators for successful chilli production; fallow land, gardens and pasture therefore need to be valued as important habitats for these and related ground-nesting bee species. However

Remnant tree presence affects forest recovery after slash-and-burn agriculture. However, little is known about its effect on above-ground carbon stocks, especially in Africa. We focused our study on Sierra Leone, part of the Upper Guinean forests, an important centre of endemism threatened by encroachment and forest degradation. We studied 99 (20-m-radius) plots aged 2-10 years with and without remnant trees and compared their above-ground carbon stocks, vegetation structure (stem density, basal area) and tree diversity. Above-ground carbon stocks, stem density, basal area, species richness and tree diversity increased significantly with fallow age. Remnant tree presence affected significantly tree diversity, species dominance and above-ground carbon stocks, but not vegetation structure (stem density, basal area). Number of remnant trees and number of species of remnant trees were also important explanatory variables. Although other factors should be considered in future studies, such as the size and dispersal modes of remnant trees, our results highlight that more strategic inclusion of remnant trees is likely to favour carbon stock and forest recovery in old fallows. To our knowledge, this is the first study on early succession regrowing fallows in West Africa.

Questions: Secondary succession in the tropics can follow alternative pathways. Land-use history is known to engender alternative successional communities, but the underlying mechanisms driving and sustaining divergence remain unclear. In this study we aim to answer the following questions: (1) does previous land use act as a filter for species composition in secondary forests; and (2) what are the relative roles of management practices, soil properties and landscape composition in determining species composition?. Location: Central Amazon, Brazil. Methods: We sampled trees, shrubs and palms (≥1cm diameter) in 38 early secondary forests (5 yr after abandonment) located along gradients of land-use intensity in five shifting cultivation landscapes. We measured the diameter and height of each sampled plant, identified it to species or morpho-species level and checked if it was resprouting or not. At each secondary forest we also collected soil samples for chemical and physical analyses and estimated the amount of old-growth forest surrounding it (landscape composition). Results: We found that previous land-use intensity determined species composition. With increasing land-use intensity, management practices of cut-and-burn and associated reduction in soil quality filtered out seed-dependent species and favoured strong sprouters and species that can cope with low nutrient availability. Landscape composition had a weak effect on species assemblages. We found specific species assemblages and indicator species associated with different levels of previous land-use intensity. As a consequence of these local filters, species α- and β-diversity decreased and therefore early successional communities became more similar to each other. Conclusion: Species composition of successional forests is strongly determined by different land-use intensities. Dispersal limitation has a limited effect on determining the composition of the dominant species. Filtering effects of management p

This study deciphers the westbound journey of the Swedish Linnaeus disciple Pehr Kalm, comparing his ontology to that of another category of Swedes crossing the Atlantic: the forest Finns. While Pehr Kalm's travels are financed by The Royal [Swedish] Academy [of Sciences], the forest Finns are initially deported to the "New Sweden" colony. Kalm is seized by "terror" - in the words of Johann Reinhold Forster - while discovering the "New World" while the forest Finns encounter a fellow slash-and-burn community of Lenape Indians. Questions raised in this study circle around the ontologies immanent in "core" vs. "peripheral" ways of life.

In northern Laos, shortened fallows in the slash-and-burn upland rice system are not sustainable either from a production or economic standpoint. This paper evaluates the potential for using the indigenous fast-growing tree, Broussonetia papyrifera L. Vent. (paper mulberry) as an economic fallow crop. The objectives of this study are to assess the inner bark yield of paper mulberry, and to evaluate rice productivity following paper mulberry cultivation. In addition, allometric models for estimating the inner bark yield of paper mulberry are developed. Inner bark yield of paper mulberry stands ranging in age from 9 to 48 months ranged from 10 to 208 g m−2, and increased with age. The models using diameter at breast height and stem height, or diameter at breast height only as independent variables explained well the variation in inner bark yield. When paper mulberry was completely removed during the rice growing season, rice yields in these areas were similar to those following weedy bush fallow. When paper mulberry was allowed to grow, rice yields were negatively correlated to paper mulberry stem density. When paper mulberry lateral branches were pruned back, rice yields could be maintained if the paper mulberry stem density was <0.22 stems m−2, suggesting that if paper mulberry is managed properly, rice yields can be maintained at current levels. The paper mulberry-upland rice rotation system improves the productivity of a traditional slash-and-burn system through harvesting paper mulberry inner bark; however the long-term sustainability of such a system remains unclear and warrants further investigation.

In northern Laos, shortened fallows in the slash-and-burn upland rice system are not sustainable either from a production or economic standpoint. This paper evaluates the potential for using the indigenous fast-growing tree, Broussonetia papyrifera L. Vent. (paper mulberry) as an economic fallow crop. The objectives of this study are to assess the inner bark yield of paper mulberry, and to evaluate rice productivity following paper mulberry cultivation. In addition, allometric models for estimating the inner bark yield of paper mulberry are developed. Inner bark yield of paper mulberry stands ranging in age from 9 to 48 months ranged from 10 to 208 g m−2, and increased with age. The models using diameter at breast height and stem height, or diameter at breast height only as independent variables explained well the variation in inner bark yield. When paper mulberry was completely removed during the rice growing season, rice yields in these areas were similar to those following weedy bush fallow. When paper mulberry was allowed to grow, rice yields were negatively correlated to paper mulberry stem density. When paper mulberry lateral branches were pruned back, rice yields could be maintained if the paper mulberry stem density was <0.22 stems m−2, suggesting that if paper mulberry is managed properly, rice yields can be maintained at current levels. The paper mulberry-upland rice rotation system improves the productivity of a traditional slash-and-burn system through harvesting paper mulberry inner bark; however the long-term sustainability of such a system remains unclear and warrants further investigation.

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention., [ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention., [ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention., [ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention., [ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.

[EN] Forest based agricultural systems in the tropics are being opened up to international trade at an unprecedented rate.This is the case of tropical agriculture in Mexico under the North American Free Trade Agreement (NAFTA), which is also having significant impacts on the decentralized land use decisions of small-scale farmers and on the natural resource base on which they depend. This paper develops a bioeconomic model of a typical forest-land based farming system that is integrated with the non-farm labour sector, as typically found in tropical regions. The data used to generate the simulations were gathered in two communities of Yucatan (Mexico) in 1998-2000. Through a systemdynamics framework, the agro-ecological and farming economic subsystems are integrated and the current situation of price liberalization that is negatively affecting soil capital and income levels is compared to a scenario that precludes an «optimal path to extinction» through careful policy intervention. This second-best case is based on a targeted policy mix that seeks to maintain the system viable for as long as possible above an irreducible poverty level. The policy intervention involves, simultaneoulsy, subsidizing off-farm wage rates, intensification of land use, and the control of households’ rights to the forest commons. The model shows that such policy intervention can result in a large positive discounted net payoff basedon the increased incomes for the farming community after deducting the implementation costs of such intervention., [ES] Los sistemas agro-forestales tropicales están siendo expuestos al comercio internacional a un ritmo sin precedentes. Este es el caso de la agricultura en México en el contexto del Tratado de Libre Comercio de América del Norte (TLCAN) que está teniendo impactos importantes sobre las decisiones descentralizadas de los campesinos y la base de los recursos naturales del cual dependen. El presente artículo desarrolla un modelo bio-económico basado en un típico sistema agro-forestal del trópico que, a su vez, se encuentra integrado con el sector laboral no-agrícola. Los datos empleados para generar las simulaciones han sido obtenidos en dos comunidades campesinas de Yucatán (México) entre los años 1998-2000. Mediante un marco teórico dinámico se integran el subsistema de producción campesina y el agroecológico. El objetivo es poder comparar la situación actual, con políticas macroeconómicas de liberalización de precios agrícolas (p.ej., maíz) que están afectando negativamente tanto el capital natural y el nivel de renta de los hogares campesinos, con un posible escenario basado en intervenciones de política económica con el objetivo de evitar una posible «senda óptima de extinción» del capital natural. Se trata de poner en práctica de forma simultánea varias políticas «second-best» manteniendo viable el sistema productivo durante el mayor tiempo posible y manteniendo, a su vez, los hogares por encima del umbral de pobreza. La integración de varias políticas implica (a) intervenir los salarios nominales fuera de la agricultura, (b) la intensificación del uso de la tierra, y (c) el control de los derechos de propiedad de los hogares sobre la tierra comunal. El modelo demuestra que este tipo de intervención «second best» es rentable si se tienen en cuenta la renta generada por las comunidades campesinas y el coste de la puesta en práctica de dichas políticas.

The conversion of primary forest to other land uses in the Amazon threatens biodiversity and releases carbon into the atmosphere, but makes economic development and poverty reduction possible. Small-scale farmers practising slash-and-burn cultivation account for a significant proportion of tropical deforestation. However, the conditions necessary for increased productivity of alternative land use systems (LUS) to improve farmer welfare and simultaneously reduce deforestation are not well understood. The research presented in this report attempts to determine the environmental consequences of different LUS in the western Brazilian Amazon, whether these consequences can be mitigated with appropriate technological, policy and institutional changes and what sorts of tradeoffs exist among the different social objectives facing policy makers. The research programme implemented during Phase II of ASB s project in Brazil was designed to better understand how the Government of Brazil, national and international research organizations and donor agencies can balance global environmental objectives with economic development and poverty reduction. The key question can be summarized as: can intensifying land use within forest and on cleared land simultaneously reduce deforestation and reduce poverty?

The conversion of primary forest to other land uses in the Amazon threatens biodiversity and releases carbon into the atmosphere, but makes economic development and poverty reduction possible. Small-scale farmers practising slash-and-burn cultivation account for a significant proportion of tropical deforestation. However, the conditions necessary for increased productivity of alternative land use systems (LUS) to improve farmer welfare and simultaneously reduce deforestation are not well understood. The research presented in this report attempts to determine the environmental consequences of different LUS in the western Brazilian Amazon, whether these consequences can be mitigated with appropriate technological, policy and institutional changes and what sorts of tradeoffs exist among the different social objectives facing policy makers. The research programme implemented during Phase II of ASB s project in Brazil was designed to better understand how the Government of Brazil, national and international research organizations and donor agencies can balance global environmental objectives with economic development and poverty reduction. The key question can be summarized as: can intensifying land use within forest and on cleared land simultaneously reduce deforestation and reduce poverty?